The proposed research for the 02 year of this grant is aimed at polygraphically evaluating dogs with canine narcolepsy and age-matched, sex-matched normal control dogs. We will continue to study the pattern of reflex suppression in REM sleep and cataplexy by using the Paillard technique and on dogs held in atraumatic restraint. We will continue a breeding program to increase the number of affected dogs and assess genetic factors in the disorder. We will continue to broaden our efforts to find affected dogs through cooperating veterinarians. We also plan to study the anticataplectic effects of tricyclic antidepressants on affected Doberman Pinschers and to assess any breed differences in the manifestations and drug responsiveness of the disorder. BIBLIOGRAPHIC REFERENCES: Mitler, M., Soave, O. and Dement, W. Narcolepsy in seven dogs. J. Am. Vet. Assoc. 168:1036-1038, 1976. Mitler, M. and Dement, W. Sleep studies on canine narcolepsy: pattern and cycle comparisons between affected dogs and normal controls. Submitted to Electroencephalogr. Clin. Neurophysiol. 1/77.